Enhancement and Induction of HIV‐1 Infection through an Assembled Peptide Derived from the CD4 Binding Site of gp120

Contact between the human immunodeficiency virus (HIV‐1) and its target cell is initiated by the interaction of viral gp120 with cellular CD4. An assembled peptide (CD4bs‐M) that presents the CD4 binding site of gp120 was previously shown to inhibit the gp120–CD4 interaction. Here, we demonstrate that CD4bs‐M selectively enhances infection of cells with HIV‐1, whereas infection with herpes simplex virus remains largely unaffected. The effects of CD4bs‐M variants containing D ‐amino acids, or prolines at selected positions, point to the importance of side chain orientation and spatial orientation of this fragment. Furthermore, CD4bs‐M was shown to assemble into amyloid‐like fibrils that capture HIV‐1 particles, which likely contributes to the infection‐enhancing effect. Beyond infection enhancement, CD4bs‐M enabled HIV‐1 infection of CD4‐negative cells, suggesting that binding of the peptide to gp120 facilitates interaction of gp120 with coreceptors, which might in turn enhance HIV‐1 entry.     

Systematic Evaluation of Fluorination as Modification for Peptide-Based Fusion Inhibitors against HIV-1 Infection

With the emergence of novel viruses, the development of new antivirals is more urgent than ever. A key step in human immunodeficiency virus type 1 (HIV-1) infection is six-helix bundle formation within the envelope protein subunit gp41. Selective disruption of bundle formation by peptides has been shown to be effective; however, these drugs, exemplified by T20, are prone to rapid clearance from the patient. The incorporation of non-natural amino acids is known to improve these pharmacokinetic properties. Here, we evaluate a peptide inhibitor in which a critical Ile residue is replaced by fluorinated analogues. We characterized the influence of the fluorinated analogues on the biophysical properties of the peptide. Furthermore, we show that the fluorinated peptides can block HIV-1 infection of target cells at nanomolar levels. These findings demonstrate that fluorinated amino acids are appropriate tools for the development of novel peptide therapeutics.     

Vorgehensweise zur gesundheitlichen Bewertung von VOC‐ und SVOC‐Emissionen aus Bauprodukten: Bewertungskonzept des Ausschusses zur gesundheitlichen Bewertung von Bauprodukten (AgBB)

Procedure for assessing potential health effects of VOC and SVOC emissions from building products ‐ assessment concepts proposed by the German Committee for Health‐related Evaluation of Building Products (AgBB). Building products for internal spaces can act as significant emission sources of volatile organic substances and seriously affect the quality of the room air. Public law requirements for building products regarding health protection of occupants are anchored in the European Construction Products Directive (89/106/EEC) and through implementation in national law, for example the Building Products Act or the regional building regulations. The European Construction Products Directive defines the requirements relating to health, hygiene and the environment, which are elaborated in Baseline Requirements Document No.3 of the European Commission. In particular, they include the requirements regarding emissions of noxious substances from building products and the avoidance and limitation of volatile organic connections (VOC) in internal spaces. Since no official procedure currently exists for the implementation of these health‐related requirements, the German Committee for Health‐related Evaluation of Building Products (AgBB) substantiated and published test criteria for the assessment of potential health effects of volatile organic compounds (VOC and SVOC emissions) from building products. In line with building laws, this procedure provides standardised test procedures and health‐related assessment criteria with the aim of limiting emissions of volatile organic compounds from building products. Against the background of building authority requirements, this objectifiable and particularly transparent approach will enable consumers, architects, planners and building product manufacturers to evaluate building products for internal spaces at an early stage for their relevance in terms of pollutants and emissions, and to use them appropriately.     

Surface chemistry of phase-pure M1 MoVTeNb oxide during operation in selective oxidation of propane to acrylic acid

The surface of a highly crystalline MoVTeNb oxide catalyst for selective oxidation of propane to acrylic acid composed of the M1 phase has been studied by infrared spectroscopy, microcalorimetry, and in situ photoelectron spectroscopy. The acid–base properties of the catalyst have been probed by NH₃ adsorption showing mainly Brønsted acidity that is weak with respect to concentration and strength of sites. Adsorption of propane on the activated catalyst reveals the presence of a high number of energetically homogeneous propane adsorption sites, which is evidenced by constant differential heat of propane adsorption q_diff,initial = 57 kJ mol^?1 until the monolayer coverage is reached that corresponds to a surface density of approximately 3 propane molecules per nm² at 313 K. The decrease of the heat to q_diff,initial = 40 kJ mol^?1 after catalysis implies that the surface is restructured under reaction conditions. The changes have been analyzed with high-pressure in situ XPS while the catalyst was working applying reaction temperatures between 323 and 693 K, different feed compositions containing 0 mol.% and 40 mol.% steam and prolonged reaction times. The catalytic performance during the XPS experiments measured by mass spectrometry is in good agreement with studies in fixed-bed reactors at atmospheric pressure demonstrating that the XPS results taken under operation show the relevant active surface state. The experiments confirm that the surface composition of the M1 phase differs significantly from the bulk implying that the catalytically active sites are no part of the M1 crystal structure and occur on all terminating planes. Acrylic acid formation correlates with surface depletion in Mo⁶⁺ and enrichment in V⁵⁺ sites. In the presence of steam in the feed, the active ensemble for acrylic acid formation appears to consist of V⁵⁺ oxo-species in close vicinity to Te⁴⁺ sites in a Te/V ratio of 1.4. The active sites are formed under propane oxidation conditions and are embedded in a thin layer enriched in V, Te, and Nb on the surface of the structural stable self-supporting M1 phase.     

High yield preparation of all-organic raspberry-like particles by heterocoagulation via hydrogen bonding interaction

We describe here a straightforward strategy towards the high yield preparation of raspberry-like all-organic particles. Poly(acrylic acid)-b-poly(butyl acrylate) core–shell nanoparticles (D ∼ 80 nm) and larger poly(ethylene oxide)-b-poly(butyl acrylate) core–shell (D ∼ 230 nm), synthesized by RAFT emulsion polymerization, were mixed at high solids content (23 wt%) at room temperature without any particular precaution (no dropwise addition, no pH adjustment). Raspberry-like particles constituted of one central PEO-b-PBA particle surrounded by about thirty PAA-b-PBA particles were successfully obtained, with no coagulum formation. The heteroaggregation process is probably driven by the hydrogen-bond interactions between the PAA and the PEO shells of the particles. The raspberry-like particles were characterized using electron microscopy (TEM and cryo-TEM), dynamic light scattering (DLS), chromatography (HDC) and calorimetry (ITC), demonstrating the selectivity of the process.     

Hypergravity to Explore the Role of Buoyancy in Boiling in Porous Media

Boiling in porous media is an active topic of research since it is associated with various applications, e.g. microelectronics cooling, wetted porous media as thermal barriers, food frying. Theoretical expressions customary scale boiling heat and mass transfer rates with the value of gravitational acceleration. Information obtained at low gravity conditions show a deviation from the above scaling law but refers exclusively to non-porous substrates. In addition, the role of buoyancy in boiling at varying gravitational levels (i.e. from microgravity—important to satellites and future Lunar and Martial missions, to high-g body forces—associated with fast aerial maneuvers) is still unknown since most experiments were conducted over a limited range of g-value. The present work aims at providing evidence regarding boiling in porous media over a broad range of hypergravity values. For this, a special device has been constructed for studying boiling inside porous media in the Large Diameter Centrifuge (LDC at ESA/ESTEC). LDC offers the unique opportunity to cancel the shear stresses and study only the effect of increased normal forces on boiling in porous media. The device permits measurement of the temperature field beneath the surface of the porous material and video recordings of bubble activity over the free surface of the porous material. The preliminary results presented from experiments conducted at terrestrial and hypergravity conditions, reveal for the first time the influence of increased levels of gravity on boiling in porous media.     

Emotional Intensity of Idiographic Sad Memories in Depression Predicts Symptom Levels 1 Year Later.

When cued with generic happy and sad words, depressed individuals have been found to articulate contextually impoverished memories of autobiographical events. Although this pattern predicts a worse symptomatic course of disorder in some depressed samples, longitudinal findings with the cue-word paradigm are inconsistent. To address the etiological significance of autobiographical memories outside the cue-word paradigm, the authors used an idiographic interview in which depressed participants generated memories of their happiest and saddest lifetime events. Each memory was coded for detail and emotional intensity. At a 1-year follow-up, participants' levels of depressive symptoms were reassessed. Lower emotional intensity of saddest memories predicted higher levels of depressive symptoms at follow-up. Several implications for understanding sadness and emotional disclosure in depression are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Health stresses and depressive symptomatology in the elderly: The importance of health engagement control strategies.

The study presents cross-sectional (N=127) and longitudinal (n=111) analyses examining relations between health engagement control strategies (HECSs), depressive symptoms, and health stresses in elderly individuals. HECS was measured as people's behavioral and cognitive investments toward attaining health goals. HECS was related to low levels of depressive symptoms, particularly among people experiencing acute physical symptoms. Moreover, HECS predicted reduction of depressive symptoms over time, and depressive symptomatology predicted negative change in HECS. The findings show that active investments of HECSs significantly moderate the negative affective consequences of health threats. Individuals who are characterized by low levels of HECS and high levels of depressive symptoms may be at increased risk of accelerated decline in their physical and mental health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)